Carriage assembly for controlling a steering wire steering mechanism within a flexible shaft

ABSTRACT

A carriage assembly for controlling a steering wire steering mechanism within a flexible shaft, for use in gastrointestinal tract surgery, comprises a plurality of selectably engageable motors, including two drive motors for selectably rotating drive shafts of a surgical attachment, two steering motors mechanically communicating with corresponding pulleys around which are coiled directional steering wires communicating with a flexible shaft to enable the selective direction of the flexible shaft within a spatial plane, wherein within the assembly housing the steering motors travel on a steering motor carriage and the pulleys travel on a pulley carriage which is biased by a spring means away from the interior wall of the housing, which biases the steering wires toward a taut state. The bias can be overcome by a carriage motor mechanically communicating with the pulley carriage to cause the flexible shaft to go limp. Also disclosed are a series of surgical attachments which may be coupled to and utilized in conjunction with the carriage assembly.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of co-pending applicationU.S. Ser. No. 09/324,452 filed Jun. 2, 1999 entitled “AnElectromechanical Driver Device for use with Anastomosing, Stapling, andResecting Instruments”.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to electromechanical devices foruse with surgical instruments and more specifically to a carriageassembly for controlling a steering wire steering mechanism within aflexible shaft, suitable for use with an electromechanical driverassembly by which surgical attachments incorporating anastomosing,stapling, and resecting tools may be remotely actuated.

2. Description of the Prior Art

Upon identification of cancerous or other anomalous tissue in thegastrointestinal tract, surgical intervention is often prescribed. Thefield of cancer surgery, and more specifically, the surgical procedureby which a section of the gastrointestinal tract which includescancerous or anomalous tissue is resected, includes a number of uniquelydesigned instruments. In combination with a description of the presentinstrumentation and their functions, a description of the state of theart in this surgical procedure shall also be provided.

The first question which must be answered when determining how to treatgastrointestinal cancer relates to the specific location of thecancerous tissue. This is very important insofar as the instrumentswhich are provided in the present art have limitations relating to howfar they may be inserted into the gastrointestinal tract. If thecancerous tissue is too far up the colon, for example, then the standardinstrumentation provided is unusable, thus requiring specialaccommodations. These accommodations generally increase the risk ofcontamination of the surrounding tissues with bowel contents, increasethe length of the surgery and the corresponding need for anesthesia, andeliminate the benefits of precise anastomosing and stapling which comesfrom utilizing a mechanized device.

More specifically, in the event that the cancerous tissue is located ata position in the colon which is accessible by the presentinstrumentation, the patient's abdomen is initially opened to expose thebowel. The surgeon then utilizes a linear cutter and stapling devicewhich cuts the tube of the colon on either side of the cancerous tissue,thereby creating two stapled ends of the bowel (a distal end which isdirected toward the anus, and the proximal end which is closest to thesmall intestine). This is done in order to temporarily minimizecontamination.

More particularly, referring to FIG. 1, the bowel is placed between thescissoring elements 12, 14 at the tip of the linear stapling instrument10. By squeezing the trigger 16 in the handle 18 of the device, thesurgeon causes the scissoring elements 12,14 to come together. A secondtrigger (or a secondary action of the same trigger) is then actuated todrive a series of staples 20 through the clamped end of the colon,thereby closing and transecting the ends.

The surgeon then partially opens the proximal end and inserts theremovable anvil portion of an anastomosing and stapling instrument intothe exposed proximal end. This step, as well as those of the remainderof the surgical procedure, are related to the functioning of thissurgical instrument. More particularly, and with respect to FIG. 2, thesurgeon begins by taking the instrument 30 and manually turning the dial32 at the base of the handle 34 which causes the anvil head 36 at theopposite end to advance forward. The surgeon continues to turn the dial32 until the anvil head 36 advances to its most extreme extendedposition. This manual turning requires nearly thirty full rotations.Once fully extended, the anvil head of the instrument is decoupledtherefrom and is inserted into the partial opening of the proximal endsuch that the coupling post extends outwardly therethrough. This partialopening of the proximal end is then sutured closed. The extending shaft38 of the anastomosing and stapling instrument 30 is then inserted andadvanced into the lower colon, transanally, until the coupling stem 40thereof extends through the stapled distal end. The surgeon then joinsthe coupling ends of the anvil and shaft together and begins to manuallyrotate the dial in the handle again, this time bringing the anvil headcloser to the end 42 of the shaft.

Once the anvil head and shaft are brought close together, after thesurgeon has manually rotated the dial another thirty times, a grip-styletrigger 44 in the handle is manually actuated. This actuation causes acircular blade 46 to advance axially out from the tip of the shaft, intocontact with the opposing face 48 the anvil 36. The blade cuts throughthe stapled-closed ends of the proximal and distal ends of the colon,thereby also cutting a new pair of ends of the proximal and distalportions of the colon. The tissue which has been severed is held in aninterior volume at the end of the shaft.

In lock step with the cutting, the freshly opened ends are joinedtogether by a series of staples 50 which are advanced through holes inthe perimeter of the tip of the shaft (being pressed against and closedby the opposing face of the anvil). The coupled shaft and anvil are thenwithdrawn from the patient.

More particularly with respect to the structural features of the linearstapling instrument 10 of the prior art which is provided in FIG. 1, thedevice comprises a pistol grip-styled structure 18 having an elongateshaft 19 and distal portion 20. The distal portion includes a pair ofscissors-styled gripping elements 12, 14 which clamp the open ends ofthe colon closed. In fact only one of the two scissors-styled grippingelements, the upper jaw portion 12, moves (pivots) relative to overallstructure; the other remains fixed. The actuation of this scissoringmeans (the pivoting of the upper jaw 12 portion) is controlled by meansof a grip trigger 16 maintained in the handle. A number of differentmeans have been disclosed for holding the tips of the scissoring armsclosed, including snaps, clips, collars, et al.

In addition to the scissoring means, the distal portion also includes astapling mechanism. The non-moving lower jaw 14 of the scissoringmechanism includes a staple cartridge receiving region and a mechanismfor driving the staples 20 up through the clamped end of the colon,against the upper jaw portion, thereby sealing the previously openedend. The scissoring elements may be integrally formed with the shaft, ormay be detachable such that various scissoring and stapling elements maybe interchangeable.

More particularly with respect to the structural features of theanastomosing and stapling instrument of the prior art which is providedin FIG. 2, the device comprises an anvil portion 36, a staple, blade andreservoir portion 42, a shaft portion 38, and a handle portion 34. Theanvil portion 36, which is selectively removable from the tip of theshaft, is bullet shaped, having a blunt nosed top portion, a flatcutting support surface 48 on the bottom, and a coupling post 41extending axially from the bottom surface.

The staple, blade, and reservoir portion 42 (SBR portion) of theinstrument is provided at the distal end of the instrument, and includesa selectively advanceable and retractable coupling stem 40 forselectively receiving thereon the anvil portion. This action of thecoupling stem is provided by a screw threaded shaft and wormingmechanism mounted in the handle 34 (described more fully below). The SBRportion is cylindrical in shape, forming a housing which has a hollowinterior. It is this hollow interior which forms the reservoir 47. Theblade 46 is similarly cylindrical, and seats in the inside of thehousing, against the inner wall thereof. The blade is selectivelyadvanceable axially outward from the housing, in accordance withactuation of a trigger 44 mechanism of the handle (again, described morefully below). On the axially outward facing surface of the cylindricalwall of the housing are a series of staple ports, through which thestaples 50 of the device are discharged. The same actuation which drivesthe blade forward similarly drives a series of staple drivers forwardwithin the cylindrical walls. More accurately, the staple driver is acylindrical component which has a series of protuberances on the axialend thereof, the protuberances being positioned in accordance with thedistribution of staples and holes. The staples, prior to beingdischarged, are mounted in the holes; and they are advanced through theholes by the action of the staple driver and the protuberances thereof.

The shaft portion 38 of the instrument is a simple rigid extendedstructure which is intended as a sheath for a pair of elongate rods. Thefirst rod is coupled to the worming mechanism introduced above, anddescribed more fully below with respect to the handle portion, and isthe means by which the anvil portion and the coupling stem of the SBRportion are selectively advanced and retracted. The second rod iscoupled to the trigger 44 of the handle at one end (also introducedabove, and described more fully below) and to the blade 46 and stapledriver 45 at the other end. The sheath protects the patient and theinstrument when it is advanced into the colon transanally. The nature ofthe actuation mechanisms however, requires that the shaft be rigid. Thisrigidity limits the length of the shaft 38; and combination, i.e. thelength and rigidity of the instrument, these features limit the sectionsof the colon which may be treated using this device.

The handle 34 of this instrument of the prior art comprises a pistolgrip styled structure having a turning dial 32 at the butt (i.e. the endopposing the junction of the shaft portion which the handle) and afinger actuated trigger 44. The trigger includes a safety mechanismwhich physically prevents actuation unless moved out of the interferenceposition. The turning dial 32 is actionably coupled to a wormingmechanism which is used to advance the first rod of the shaft portion(thereby advancing the coupling stem and the anvil 36). The triggerfunctions as a basic lever to S push the second rod forward within theshaft, thereby advancing the blade 46 and staple driver 45.

As with many such devices of the prior art, all of these devices areconsidered fully disposable, and are, in fact, thrown away after asingle use. They are complicated devices, having multiple moving parts,requiring substantial structural integrity and, therefore, expense inmanufacturing. The fact that they are used only once, and no part can beused again render the use of such devices expensive and wasteful ofresources.

In addition to this failure, as can be readily observed from thepreceding descriptions, the prior art devices suffer from numerous otherlimitations which would be desirable to overcome. These include therequirement that the surgeon manually actuate a number of differentfunctions (including those associated with the dial and trigger of theanastomosing and stapling instrument and the multiple triggers of thelinear cutting and stapling instrument).

Therefore, it is a principal object of the present invention to providean instrument for cutting, anastomosing, and stapling, for use ingastrointestinal surgery, which reduces the waste of resources bypermitting the reuse of portions thereof.

It is further an object of the present invention to provide aninstrument assembly which reduces the requirements for the surgeon tomanually actuate different components and mechanisms.

Other objects of the present invention shall be recognized in accordancewith the description thereof provided hereinbelow, and in the DetailedDescription of Preferred Embodiments in conjunction with the remainingFigures.

SUMMARY OF THE INVENTION

The preceding objects of the invention are provided by a carriageassembly which is suitable for mounting within an electromechanicaldriver assembly which couples to and actuates both a linear staplingattachment and an anastomosing and stapling attachment. It may berecognized by the astute reader that both of the instruments of theprior art, which have been described above, have similar dual actions.More particularly, the linear stapling instrument first clamps and thenstaples, and the anastomosing and stapling instrument advances andretracts an anvil portion, which is, in effect, a clamping action, andthen drives a blade and staples forward. It is, therefore, possible toconstruct a single common driver assembly which can be used to actuatethe functions of each, such that the differing functions may be specificonly to attachments, and not to the entirety of the instrument. Thepresent invention encompasses several components of such a driverassembly.

More particularly, the present invention comprises a plurality of motorsand related components which together allow the electromechanical driverassembly to drive the flexible drive shafts of the electromechanicaldriver assembly and to remotely steer the distal tip of the flexibleshaft portion of the electromechanical driver assembly. The presentinvention comprises two selectably engageable drive motors forselectably rotating drive shafts of a surgical attachment. Specifically,the drive motors each selectably rotate a drive shaft of a surgicalattachment by mechanically communicating with the flexible drive shaftof the electromechanical driver assembly which ends in a coupler at thedistal tip of the flexible drive shaft of the electromechanical driverassembly, to which the surgical attachment (such as one of the surgicalattachments disclosed herein) may be coupled.

The present invention further comprises two selectably engageablesteering motors for engaging steering wires which communicating with theflexible drive shaft of the electromechanical driver assembly.Specifically, the steering motors mechanically communicate withcorresponding pulleys around which the steering wires are coiled.Selective engagement of the steering motors selectively rotates thepulleys to selectively advance or retract the steering wires. Theadvancement or retraction of the steering wires translates to enable theselective direction of the flexible drive shaft of the electromechanicaldriver assembly within a spatial plane. That is, the flexible driveshaft can be pulled in any direction, as the surgeon operator desires.

The present further comprises a pulley carriage upon which the pulleystravel within the handle of the electromechanical driver assembly, and asteering motor carriage upon which the steering motors travel within thehandle of the electromechanical driver assembly. Inasmuch as thesteering motors are in mechanical communication with the pulleys asshown, the carriages travel together. The carriages travel on carriagesrails which are mounted to the handle of the electromechanical driverassembly. Springs surrounding that portion of the rails between theinterior wall of the electromechanical driver assembly handle and thepulley carriage bias the steering wires toward a taut state by biasingthe pulley carriage away from the interior wall. In this taut state, thesteering wires are able to direct the flexible drive shaft as describedabove. The present invention further comprises a carriage motor whichmechanically communicates with the pulley carriage to selectively allowthe pulley carriage to succumb to the bias of the springs or push thepulley carriage toward the interior wall of the handle of theelectromechanical driver assembly with a force great enough to overcomethe bias of the springs. That is, in order to permit the steering wires(and therefore the flexible drive shaft) to go limp, the surgeonoperator engages the carriage motor while the surgeon operator desiresthe steering wires to be limp.

As stated above, the components of the present invention are suitablefor mounting within an electromechanical driver assembly which couplesto and actuates linear stapling attachments and an anastomosing andstapling attachment. It is anticipated that other attachments will beused as well. The electromechanical driver assembly and the mentionedattachments are described more fully hereinbelow to enable understandingof the use of the present invention.

First, with respect to the electromechanical driver, the driver has ahandle (where the components of the present invention are mounted) and aflexible drive shaft. The handle has a pistol grip-styled design, havingfinger triggers which are independently coupled to the motors of thepresent invention which each perform the functions as described above.The motors are each dual-direction motors, and are coupled to manualdrive switches mounted to the top of the handle, by which the user canselectively alter the turning direction of each motor. Thisdual-direction capacity may be most simply achieved by selecting motorswhich turn in a direction corresponding to the direction of current, andactuation of the drive switches alters the direction of the currentaccordingly. In this example, the power source supplying the motors mustbe a direct current source, such as a battery pack (and most desirably,a rechargeable battery pack). In the event that the electromechanicaldriver assembly should be useable with an alternating current, either atransformer can be included, or a more sophisticated intermediategearing assembly may be provided. In conjunction with the presentdescription, the electromechanical driver assembly will be described asutilizing a rechargeable battery pack providing a direct current.

In addition to the motors and other components of the present invention,the handle further includes several other features, including a remotestatus indicator and at least one additional electrical supply. First,the remote status indicator may comprise an LCD (or similar read outdevice) by which the user may gain knowledge of the position ofcomponents (for example whether a clamping element is in the properposition prior to the driving of the staples). Second, the handle mayinclude an additional electrical power supply and an on off switch forselectively supplying electrical power to the attachments.

Further with regard to the steering motors of the present invention, thehandle also includes a manually actuatable steering means, for example,a joystick or track ball, for directing the movement of the flexibleshaft (by means of the steering wires of the present invention asdescribed above which continue into the flexible shaft portion).

In this embodiment of the electromechanical driver assembly, the drivercomponents are integrated with the controller components. It should benoted that other embodiments of the electromechanical driver assemblymay comprise a driver unit which is physically separate from acontroller unit. That is, the driver unit may comprise theabove-described motors and the above-described steering means, and thecontroller unit may comprise the above-described triggers, theabove-described remote status indicator, as well as the above-describedmanually actuatable steering means means. The controller unit componentscommunicate with the driver unit components by wireless transmission,for example, through infrared, radio waves, other electromagnetic waves,or ultrasound. In such a configuration, for example, the driver unit maybe located out of the surgeon's arm's reach, while the controller unitmay be selectively coupleable to that portion of the flexible shaftwhich is closer to the patient and closer to the surgeon. It should befurther understood that additional embodiments of the electromechanicaldriver assembly may comprise more than two separate units, and suchunits may each house only one, or more than one, of the above-describedseparate components, all communicating by wireless means as describedabove. For example, the remote status indicator described above could bepart of a third unit which mounts to a visor wearable by the surgeon. Itshould be further understood that all communications between thesecomponents as described herein may in such alternative embodiments takeplace by wireless means.

Further with respect to the flexible shaft, the shaft comprises atubular sheath, preferably formed of a simple elastomeric material whichis tissue compatible and which is sterilizable (i.e., sufficientlyrugged to withstand an autoclave). Various lengths of this shaft may beprovided in conjunction with the electromechanical driver assembly. Insuch a case, the flexible shaft and the handle portions should beseparable. If separable, the interface between the proximal end of theshaft and the distal end of the handle should include a coupling meansfor the functional components of the electromechanical driver assembly.

Specifically regarding the drive components of the shaft, within theelastomeric sheath are a pair of smaller fixed tubes which each containa flexible drive shaft which is capable of rotating within the tube. Theflexible drive shaft, itself, simply must be capable of translating atorque from the drive motors of the present invention to the distal endof the shaft, while still being flexible enough to be bent, angled,curved, etc. as the surgeon deems necessary to “snake” through the colonof the patient. For example, the drive shafts may comprise a woven steelfiber cable. It shall be recognized that other drive shafts may besuitable for this purpose. In order for the distal end of the driveshaft to couple with an attachment, such as the clamping and staplingdevice of the present invention (as described more fully below),however, the distal tips of the drive shafts must have a conformationwhich permits the continued translation of torque. For example, thedistal tips of the drive shafts may be hexagonal, thereby fitting into ahexagonal recess in the coupling interface of the attachment.Appropriate gearing mechanisms may be provided at the distal end of theshaft, or in the interfacing portion of the attachment, to ensure thatthe appropriate torque is provided to the attachment. As suggestedabove, in conjunction with the manually actuatable steering meansmounted to the handle, the sheath further includes the steering wires ofthe present invention which are flexible, but are coupled to the innersurface of the sheath near the distal end thereof. As described above,the steering wires may be axially translated relative to one another byactuation of the steering motors, which action causes the sheath to bendand curve accordingly.

Also as suggested above, in conjunction with the LCD indicator of thehandle, the shaft further contains an electrical lead for coupling tothe attachments. This electrical lead channels a signal from theattachment to the handle for indicating the status of the attachment(for example, whether a clamping function is holding). Similarly, asecond electrical lead may be provided to supply power to separateaspects of the attachment if so required (for example, as will bedescribed more fully with respect to one embodiment of the linearstapling attachment, the use of a selectively engageable electromagneticseal for ensuring continued clamping through the stapling process may beprovided and require power selectively provided from the handle's powersupply.

More particularly, with respect to the linear clamping and staplingattachment, which has several different potential embodiments, two ofwhich are disclosed herein as examples, the attachment is fitted withtwo drive extensions, which in operation function as extensions of theflexible drive shafts of the electromechanical driver assembly. That is,when the attachment is mated to the electromechanical driver assembly,the drive extensions are in mechanical communication with the flexibledrive shafts such that the activation of the drive shaft motorsactivates the drive extensions within the linear clamping and staplingattachment. In each embodiment of the attachment, the first driveextension enables a linear clamping mechanism, while the second driveextension enables a stapling mechanism. In one embodiment, the linearclamping mechanism comprises a scissors-cuff system whereby the pivotingupper jaw of the scissors is clamped to the fixed lower jaw of thescissors as a cuff enclosing a length of the scissors is moved from thehinged end of the scissors toward the closing end of the scissors. Thescissors can be unclamped as the cuff is returned to its originalposition. In this embodiment, the first drive extension moves the cuffforward or backward, depending on the turning direction of thecorresponding motor in the electromechanical driver.

In a second embodiment, the linear clamping mechanism comprises aseparating jaw system whereby an upper jaw is raised and subsequentlylowered to meet a lower jaw to effect a clamping. In this embodiment,the first drive extension engages a pair of threaded vertical shaftswhich raise or lower the upper jaw depending on the turning direction ofthe corresponding motor in the electromechanical driver assembly.

In each of these embodiments, the stapling mechanism comprises areplaceable tray of open staples set within the lower jaw and a set ofcorresponding staple guides fitted on the upper jaw, such that when thelinear clamping mechanism is in a closed position, the open staplesimmediately oppose the corresponding staple guides. The staplingmechanism further comprises a wedge pushing system whereby once thelinear clamping mechanism is in a closed position, a wedge riding in achannel below the tray of open staples is pushed through the channel. Asthe wedge moves through the channel, a sloping surface of the wedgepushes the open staples against the corresponding staple guides, therebyclosing the staples. After the staples have been closed, the wedge ispulled back through the channel. The second drive extension pushes orpulls the wedge through the channel, depending on the turning directionof the corresponding motor in the electromechanical driver, by engaginga threaded horizontal shaft upon which the wedge, having a matchinginner thread, rides.

The distal ends of the scissoring or linearly closing jaws may furtherinclude an electromagnetic securing mechanism which serves to hold thedistal tips of the jaws together during the stapling step. This ispreferred insofar as the action of driving the staples upwardly againstthe staple guides of the upper jaw may serve to open the jaws. Inaddition, the electromagnetic securing mechanism may be coupled inelectrical communication with the LCD indicator mechanism in the handle(described above) such that the surgeon operating the device may be madeaware of when the jaws have closed and the device is in a safestaple-driving position.

Referring now to the anastomosing and stapling attachment, a preferredembodiment is described hereinbelow as a single example of the differentvariations which could be constructed for the equivalent purpose. Aswith the linear stapling attachments described above, however, thisexample demonstrates the universal applicability of the overallelectromechanical driver assembly mechanism. This attachment comprisesan anvil portion, and a staple, blade and reservoir portion, whichincludes a pair of turning drive shafts which are coupleable to thedrive components of the shaft element described above, and acorresponding pair of advancing and retracting nuts mounted to theturning drive shafts, but which are prevented from rotating andtherefore linearly advance and retract along the shafts when they turn.

The anvil portion includes is bullet shaped, having a blunt nosed topportion, a flat cutting support surface on the bottom, and a freelyrotating coupling post extending axially from the bottom surface. Thiscoupling post is designed to be selectively coupleable and removablefrom the corresponding nut mounted to one of the turning drive shafts.

The staple, blade, and reservoir portion (SBR portion) is cylindrical inshape, forming a housing which has a hollow interior. It is this hollowinterior which forms the reservoir. On the axially outward facingsurface of the cylindrical wall of the housing are a series of stapleports, through which the staples of the device are discharged. A seriesof staple drivers are mounted within the cylindrical walls, beneath thestaple ports, for driving the staples therethrough. More accurately, thestaple drivers are a series of protuberances on the outer edge of asingle cylindrical component which seats in the wall of the SBR portion.The staples, prior to being discharged, are mounted in the holes; andthey are advanced through the holes by the forward motion of the stapledriver and the protuberances thereof. The blade is similarlycylindrical, and seats in the inside of the housing, against the innersurface of the wall thereof. Both the blade and the staple driver aremounted to the second nut, which is, in turn, mounted to the otherturning drive shaft. As the tuning drive shaft rotates, the nut (whichis constrained against rotating) advances along the shaft, thus linearlyadvancing the blade and staple driver. The blade and the staple driverare, therefore, selectively advanceable axially outward from thehousing, in accordance with actuation of the appropriate trigger on thehandle.

In a preferred embodiment, the anvil portion and the SBR portion furthercomprise an electromagnetic sensor mechanism, coupled to the LCDindicator of the handle, which sensor is activated when the two portionshave approached each other to the extent necessary for a safe staplefiring, whereby the surgeon may have remote knowledge of the state ofthe attachment disposed within the colon.

In practice, this attachment is utilized, once the section of the colonwhich is to be removed has been resected (but prior to the linearclamping and stapling step is complete), in the following manner. Thesurgeon begins by coupling the anastomosing and stapling attachment tothe electromechanical driver assembly and advancing the anvil portion toits fullest extent. The anvil head is then removed and inserted into thepartially opened proximal end. As described above, this proximal end isthen sutured closed. The surgeon then advances the shaft and the SBRportion of the attachment up the colon until it extends through thestapled distal end of the colon. The surgeon then couples the anvil tothe advancing and retracting nut of the corresponding drive shaft.Subsequent triggering of the motor in the handle causes the anvil toretract toward the SBR portion. As stated above, in a preferredembodiment, the base of the anvil and the outer edge of the SBR housingcomprise an electromagnetic sensor which is coupled to the LCD indicatorof the handle, thereby permitting the surgeon to know when the anvil andthe SBR have come close enough to drive the blade and staples.Subsequent actuation of the other trigger on the handle causes thecorresponding other turning drive shaft to advance the blade and stapledriver into contact with the opposing face of the anvil. The blade cutsthrough the stapled-closed ends of the colon, leaving the tissue whichhas been severed in the interior reservoir. Simultaneous with thecutting, the freshly opened ends are joined together by the series ofstaples which are advanced through holes in the perimeter edge of theSBR (being pressed against and closed by the opposing face of theanvil). The attachment and the flexible shaft are then withdrawn fromthe patient.

It should be evident that the present invention provides a necessarycomponent to the electromechanical driver assembly for the purposes ofovercoming the limitations of the prior art. Specifically, the presentinvention enhances the ability of the electromechanical driver assemblyto be reused, by providing in a compact form all of the componentsnecessary to perform the functions of the electromechanical driverassembly and the associated attachments. Therefore, the presentinvention helps to provide an instrument for cutting, anastomosing, andstapling, for use in gastrointestinal surgery, which reduces the wasteof resources by permitting the reuse of portions thereof. Further, theelectromechanical basis of the components of the present inventionreduces the requirements for the surgeon to manually actuate differentcomponents and mechanisms. That is, through the automation andpower-driver functions of the present invention, the surgeon enduresless fatigue and enjoys greater accuracy throughout the surgery.

A BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side perspective view of a linear clamping and staplinginstrument of the prior art;

FIG. 2 is a side perspective view of an anastomosing and staplinginstrument of the prior art;

FIG. 2a is a cut-away perspective view of a carriage assembly of thepresent invention;

FIG. 3 is a side view of a handle and flexible shaft of anelectromechanical driver assembly, wherein certain features of thepresent invention are shown in phantom;

FIG. 4 is a side view of one embodiment of the linear clamping andstapling attachment for use with the electromechanical driver assembly,wherein internal features of the elements are provided in phantom;

FIG. 5 is a side view of a second embodiment of the linear clamping andstapling attachment for use with the electromechanical driver assembly,wherein internal features of the elements are provided in phantom; and

FIG. 6 is a side cut-away view of an anastomosing and staplingattachment for use with the electromechanical driver assembly.

A DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

While the present invention will be described more fully hereinafterwith reference to the accompanying drawings, in which particularembodiments are shown, it is to be understood at the outset that personsskilled in the art may modify the invention herein described whileachieving the functions and results of this invention. Accordingly, thedescriptions which follow are to be understood as illustrative andexemplary of specific structures, aspects and features within the broadscope of the present invention and not as limiting of such broad scope.Like numbers refer to similar features of like elements throughout.

More particularly, the present invention, a carriage assembly forcontrolling a steering wire steering mechanism within a flexible shaft,is in the preferred embodiment suited for use with an electromechanicaldriver assembly and suitable attachments such as the linear clamping andstapling attachment and the anastomosing and stapling attachmentdisclosed herein. The interrelation of these components should be clearfrom the above description and the discussion below.

Referring now to FIG. 2a, the present invention comprises a plurality ofmotors. It is to be understood that any or all of the motors areselectably engageable by the surgeon operator via selection buttons orthe like on the exterior surface of the handle of the electromechanicaldriver assembly, and are connected to the power source or power sources(not shown) of the electromechanical driver assembly. The power sourceis preferably, but is not required to be, a removable and rechargeabledirect current battery source. It shall be understood that alternativepower sources, including dual direct current sources or single remotealternating current sources (such as the alternating current providedfrom standard United States 120 Volt, 60 Hertz wall outlets) may be usedin conjunction with alternative embodiments. In the event that theelectromechanical driver assembly should be useable with an alternatingcurrent, either a transformer can be included between the motors of thepresent invention and the power source, or a more sophisticatedintermediate gearing assembly may be provided between the motors of thepresent invention and any extended turning drive shafts.

The carriage assembly comprises two selectably engageable drive motors100 for selectably rotating drive shafts of a surgical attachment (notshown). Specifically, the drive motors 100 each selectably rotate adrive shaft of a surgical attachment by mechanically communicating witha drive shaft 120 which mechanically couples to the flexible drive shaft(shown on FIG. 3) of the electromechanical driver assembly which ends ina coupler (shown on FIG. 3) at the distal tip of the flexible driveshaft of the electromechanical driver assembly, to which the surgicalattachment (such as one of the surgical attachments disclosed herein)may be coupled.

The carriage assembly further comprises two selectably engageablesteering motors 130 for engaging steering wires 140 communicating with aflexible shaft of an electromechanical driver assembly (shown on FIG.3). Specifically, the steering motors 130 mechanically communicate viasteering shafts 150 connected by torque-translating joints (not visible)to corresponding pulleys 160 around which the steering wires 140 arecoiled as shown. Selective engagement of the steering motors 130selectively rotate the steering shafts 150 which selectively rotate thepulleys 160 to selectively advance or retract the steering wires 140.For example, when the pulley 160 as shown is rotated toward the steeringmotor 130, the upper portion 170 of the steering wire 140 is pulledtoward the steering motor 130 and the lower portion 180 of the steeringwire 140 is pulled away from the steering motor 130. This engagementtranslates to enable the selective direction of the flexible shaft ofthe electromechanical driver assembly within a spatial plane. That is,for example, the pulling of the upper portion 170 as described pulls theflexible shaft of the electromechanical driver assembly upward, whilethe pulling of the lower portion 180 as described pulls the flexibleshaft downward. It is to be appreciated further in this example thatwhen the other pulley 160 is rotated, the flexible shaft is pulled tothe left or right, as the surgeon operator desires.

The carriage assembly further comprises a pulley carriage 190 upon whichthe pulleys 160 travel within the handle of the electromechanical driverassembly, and a steering motor carriage 200 upon which the steeringmotors 130 travel within the handle of the electromechanical driverassembly. To be clear, inasmuch as the steering motors 130 are inmechanical communication with the pulleys 160 as shown, the carriages190, 200 travel together. The carriages 190, 200 travel on carriagesrails 210 which are mounted to the handle of the electromechanicaldriver assembly. Springs 220 surrounding the rails 210 as shown bias thesteering wires 140 toward a taut state by biasing the pulley carriage190 away from the interior wall of the handle of the electromechanicaldriver assembly. In this taut state, the steering wires 140 are able todirect the flexible shaft of the electromechanical driver assembly asdescribed above. The carriage assembly further comprises a carriagemotor 240 which mechanically communicates with the pulley carriage 190to selectively allow the pulley carriage 190 to succumb to the bias ofthe springs 220 or push the pulley carriage 190 toward the interior wallof the handle of the electromechanical driver assembly with a forcegreat enough to overcome the bias of the springs 220. That is, in orderto permit the steering wires 140 (and therefore the flexible shaft) togo limp, the surgeon operator engages the carriage motor 240 while thesurgeon operator desires the steering wires 140 to be limp.

The carriage assembly described above is preferably fixed within anelectromechanical driver assembly. Referring now to FIG. 3, with respectto the electromechanical driver assembly 100, the electromechanicaldriver assembly has a handle portion 102 and a flexible drive shaftportion 104. The handle 102 includes a portion which is shaped in amanner which is easily gripped by the surgeon operator, for example, inthe embodiment provided herein the handle comprises a pistol gripstyledportion 106. The grip portion 106 includes at least two, and in theembodiment shown exactly two, independently finger actuatable triggers108 a, 108 b. The finger triggers 108 a, 108 b are independently coupledto the drive motors of the present invention (see items 100 on FIG. 2aas described above) shown here as items 110 and 112, housed within theinterior volume of the handle 100. As described above and shown here,each drive motor 110, 112 (items 100 on FIG. 2a) turns a separateflexible drive shaft (described more fully hereinbelow).

Although not shown on FIG. 3, the other components of the carriageassembly of the present invention are also fixed within the handleportion of the electromechanical driver assembly, including the steeringmotors and carriage motor. The drive motors and these additional motorsare dual-direction motors, and all are coupled to finger actuatableswitches similar to the finger actuatable triggers 108 a, 108 b shown onFIG. 3. The motors are also each separately coupled to the power source114 (which is a common source in the shown embodiment) and manualswitches similar to the manual drive switch 116 shown on FIG. 3. Themanual drive switch 116 is provided on the top of the handle 100, suchthat the surgeon operator can selectively alter the turning direction ofeach drive motor. Additional manual switches can similarly be used bythe surgeon operation to selectively alter the turning direction of theother motors. In the shown embodiment, the power source 114 supplyingthe motors is a single removable and rechargeable battery pack supplyingdirect current. It shall be understood that alternative power sources,including dual-direction current sources or single remote alternatingcurrent sources (such as the alternating current provided from standardUnited States 120 Volt, 60 Hertz wall outlets) may be used inconjunction with alternative embodiments. In the event that theelectromechanical driver assembly should be useable with an alternatingcurrent, either a transformer can be included between the motors and thepower source, or a more sophisticated intermediate gearing assembly maybe provided between the motors and the extended turning drive shaft.

Further with regard to FIG. 3, in addition to the motors and othercomponents of the carriage assembly and the related power and switchelements, the handle 100 further includes a remote status indicator 118and associated electrical circuit 120. The indicator means in thisembodiment comprises an LCD mounted to the upper portion of the handle.It shall be understood that an equivalent function may be achieved bymounting an audible alarm, or other plain sensory stimulation mechanism,on the handle. The remote status indicator 118 is coupled to anassociated electrical circuit which extends along the handle and theflexible shaft and couples to a corresponding electric circuit in theselected surgical attachment (see FIGS. 4-6). The disposition of thesurgical attachment, for example in a closed or open position, isassociated with the circuit in the surgical attachment being in an opencircuit or closed circuit state. The closed circuit state causes theremote status indicator LCD to light up, whereas the open circuit statecauses the LCD to go out.

Specifically with further regard to the steering motors, pulleys,steering wires and associated components of the present invention, thehandle also includes a manually actuatable steering means, which in thepresent embodiment comprises a trackball 124 which actuates the steeringmotors of the present invention as described above, which actuates thesteering wires 126 (items 140 on FIG. 2a). The steering wires extendalong the flexible shaft portion 122 (described more fully hereinbelow)and are coupled to the tip of the flexible shaft 122. When the trackball124 is rotated, the steering wires 126 are pulled by the steering motorsof the present invention, and the tip of the flexible shaft 122 turnscorrespondingly.

More particularly, with respect to the flexible shaft 122, the shaftcomprises a tubular sheath 128 which is formed of a simple, tissuecompatible, elastomeric material. As this device is to be reused, it isimportant that the material be sterilizable (i.e., sufficiently ruggedto withstand an autoclave). While the embodiment shown comprises acontiguous handle 100 and shaft 122, it shall be understood that onehaving ordinary skill in the art may provide an alternative embodimenthaving a separable handle and shaft, thus permitting alternative shaftlengths for alternative purposes. In such cases, the flexible shaft 122and the handle 100 portions should include an interface between theproximal end of the shaft and the distal end of the handle which shouldinclude a coupling means for the electromechanical components.

Specifically regarding the drive components 130 a, 130 b of the shaft122, within the elastomeric sheath 128 are a pair of smaller fixed tubes134 a, 134 b which each contain a flexible drive shaft 136 a, 136 bwhich is capable of rotating within the corresponding tube 134 a, 134 b.Each flexible drive shaft 136 a, 136 b itself simply must be capable oftranslating a torque from the drive motors of the present invention inthe handle of the electromechanical driver assembly to the distal end138 a, 138 b of the shaft 122, while still being flexible enough to bebent, angled, curved, etc. as the surgeon deems necessary to “snake”through the colon of the patient. For example, the flexible drive shaftsmay comprise a woven steel fiber cable, a high tensile strengthpolymeric material, or a sufficiently flexible unitary metal shaft.

In order for the distal ends 138 a, 138 b of the flexible drive shafts136 a, 136 b to couple with an attachment, such as the linear clampingand stapling attachment (see FIGS. 4 and 5), the distal tips 138 a, 138b of the flexible drive shafts 136 a, 136 b must have a conformationwhich permits the continued translation of torque. In the shownembodiment, this coupling is achieved by a geometric fitting. Moreprecisely, the distal tips of the flexible drive shafts are hexagonal,and thereby fit into hexagonal recesses in the coupling interface of theattachment. In certain embodiments of the electromechanical driverassembly, the attachment and the distal end of the flexible drive shaftshould include a collar, or other aligning means, for facilitating thefitting of the attachment onto the distal end of the flexible driveshaft. Additionally, the tip of the flexible drive shaft may include thedistal ends of the circuit 120 which is coupled to the LCD 118, as wellas other coupling components necessary to translate the functionality ofthe electromechanical driver assembly to the attachments.

Referring now to FIGS. 4 and 5, two alternative linear clamping andstapling attachments are shown. The first linear clamping mechanism,shown in FIG. 4, comprises a separating jaw system comprising a lowerjaw 150 and an upper jaw 152 and a proximal interfacing end member 154.This proximal end member 154 includes two hexagonal shaped sockets 156a, 156 b into which the distal tips 138 a, 138 b of the drive shafts ofthe electromechanical driver assembly couple. Each of the sockets isformed in the end of a corresponding horizontal turning shaft 158 a, 158b. The upper horizontal turning shaft 158 a is coupled, by means of atransverse gearing member, to a threaded vertical shaft 160 whichextends through a correspondingly threaded bore 162 of the upper jaw152. The upper jaw 152 has a linear track coupling means 166 whichcorresponds and couples to a linear track 168 formed in the side of theinterface end member 154 which is opposite the driver coupling sockets156 a, 156 b. Subsequent turning of the upper horizontal turning shaft158 a causes the vertical turning shaft 160 to turn. As this shaft 160turns, the upper jaw 152 rides up and down within the track of the endmember 154.

The lower horizontal turning shaft 158 b extends axially through thelower jaw 150, which, in turn is fixed to the proximal end member 154.Mounted around this axially extending shaft 158 b is a wedge drivermechanism 166 which includes a threaded bore. This threaded member 166is locked within a track 167, which prevents the member 166 fromrotating when the shaft 158 b turns. Rather, the wedge member 166 rideslinearly along the track 167 and along the threading of the shaft 158 b.Mounted within a recess 168 in the face of the lower jaw 150 whichopposes the upper jaw 152, directly above the wedge member 166 is areplaceable tray of staples. The wedge driver has a sloped frontalsurface 172 which contacts the staple 174 and causes it to be drivenupwardly out of the tray 170. When the upper jaw 152 is in closeproximity to the lower jaw 150, the staples are closed when they contactthe opposing face of the upper jaw 152 (by the action of staple closingguide recesses 176 formed therein).

At the distal tip of the upper and lower jaws are two opposing magneticsensors 178 a, 178 b, each coupled to a circuit component which mateswith the distal ends of the LCD indicator 118 circuit 120. When the jawscome together, the circuit is closed and the LCD indicator is lighted,indicating that the staples may be safely fired.

In operation, the surgeon cuts the tube of the colon on either side ofthe cancerous tissue, thereby creating two ends of the bowel. Thesurgeon uses the linear clamping and stapling attachment to temporarilystaple the exposed ends. More particularly, the linear clamping andstapling attachment is mated to the distal end of the electromechanicaldriver assembly. By manually actuating one trigger (the one which causesthe rotation of the upper shaft 136 a) the upper jaw 152 opens relativeto the lower jaw 150. The open end of the colon is then placed betweenthe jaws 150,152 and the jaws are closed by switching the drivedirection for the upper shaft 136 a and driving the upper jaw in theopposite direction. The jaws are thereby shut on the end of the colon.At this time the LCD indicator 118 in the handle should light up,indicating that the staples may be safely advanced.

Triggering the second shaft 136 b into rotation causes the wedge driver166 to slide along the track 167 in the lower jaw 150. This drives thestaples 174 through the end of the colon and closes them against thestaple closing guide recesses 176. The jaws are then reopened and thewedge driver 166 is retracted within the lower jaw 150, the tray 170 ofstaples 174 is replaced, and the process is repeated for the other openend of the colon.

Referring now FIG. 5, the second embodiment 180 of the linear clampingand stapling attachment of the present invention is described. In thepresent embodiment the coupling interface 154 is largely equivalent tothe first embodiment inasmuch as the hexagonal ends of the shaft portionare inserted into the corresponding socket ends 156 a, 156 b of theattachment. As before, the shafts of the electromechanical driverassembly turn rotating members within the attachment. In this embodimenthowever, both turning members 158 a, 158 b are horizontal. Mounted tothe shaft interfacing member is a fixed lower jaw 150 and a moving upperjaw 152. In this embodiment, the upper jaw 152 is mounted to the lowerjaw 150 by means of a spring loaded pivot, which biases the upper jawinto an open disposition relative to the lower jaw. Mounted to the upperturning shaft however, is a linearly tracked cuff 187 which seats aroundthe upper and lower jaw, the advancement of which causes the jaws tocome together. The lower jaw includes exactly the same staple 174 trayrecess and linearly driven threaded wedge staple pushing mechanism 166.Also, the electromagnetic sensor and circuit of the first embodiment isincluded to indicate to the surgeon when the section of colon has beenfully clamped and the staples should be driven.

More particularly, after the surgeon has resected the diseased portionof the colon, the end of the colon is placed between the jaws of theattachment. By actuating the first trigger (and driving the uppershaft), the cuff member 187 advances axially along the outside of theupper and lower jaws 150,152, thus closing the upper jaw onto the colonand lower jaw. Once fully closed, the electromagnetic sensor circuitindicates to the surgeon operator that the staples may be fired, andcorrespondingly, actuation of the second trigger causes the wedge driverto advance and drive the staples through the colon section. Reversebiasing the motor for the upper turning shaft causes the cuff to retractand the upper jaw to open, thus releasing the now sealed colon end.

With reference now to FIG. 6, a preferred embodiment of the anastomosingand stapling attachment 200 is described. This attachment comprises ananvil portion 202, and a staple, blade and reservoir (SBR) portion 204,which includes a pair of turning drive shafts 206 a, 206 b which arecoupleable to the drive components 136 a, 136 b of the electromechanicaldriver assembly described above with reference to FIG. 3, and acorresponding pair of advancing and retracting members 208 a, 208 bmounted within tracks and to the turning drive shafts, which are therebyprevented from rotating and therefore linearly advance and retract alongthe shafts 206 a, 206 b when they turn. More particularly, the base ofthe SBR portion 204 includes a coupling interface 203 which includes apair of hexagonal recesses 205 a, 205 b formed in the bases of thethreaded turning shafts 206 a, 206 b.

The anvil portion 202 is bullet shaped, having a blunt nosed top portion210, a flat cutting support surface 212 on the bottom, and a couplingpost 214 extending axially from the bottom surface. This coupling post214 mounts to the first advancing and retracting member 208 a which ismounted within a linear track whereby rotation of the shaft 206 a causesthe member 208 a and the anvil 202 coupled thereto to move axially, butnot rotationally.

The staple, blade, and reservoir portion (SBR) portion 204 iscylindrical in shape, forming a housing which has a hollow interior 216.It is this hollow interior which forms the reservoir. On the axiallyoutward facing surface 218 of the cylindrical wall 220 of the housingare a series of staple ports, through which the staples 224 of thedevice are discharged. A unitary blade and cylindrical staple drivercomponent 226 is seated within the housing. More particularly, the bladeand staple driver component comprises a single element having twoconcentric cylindrical portions. The blade portion 228 seats within thehollow interior 216, against the interior wall 230 thereof. The stapledriver portion 232 seats within the wall 230 of the SBR portion andincludes a series of outwardly projecting protuberances which pushagainst staples mounted within the staple ports.

The blade 228 and staple driver portions 232 are coupled at the interiorend thereof to a threaded member 208 b which seats around turning shaft206 b. The threaded member 208 b is constrained within a linear track sothat the blade and staple driver are advanced linearly upon rotation ofthe turning shaft 206 b.

In addition, the anvil 202 and the SBR 204 portions each comprisecorresponding electromagnetic sensor circuit components 240 a, 240 bwhich couple to the LCD indicator 118 in the handle.

In practice, this attachment is utilized, once the section of the colonwhich is to be removed has been resected and stapled shut, in thefollowing manner. The surgeon begins by coupling the anastomosing andstapling attachment 200 to the electromechanical driver assembly andadvancing the anvil portion 202 to its fullest extent. The anvil head202 is then decoupled from the first advancing and retracting member 208and inserted into the exposed proximal end. As described above, thestapled proximal end of the bowel is then opened partially and the anvilhead is inserted. The bowel is then sutured closed. The surgeon thenadvances the shaft 206 a and the SBR portion 204 of the attachment upthe colon until it extends through the stapled distal end of the colon.(Alternatively, the surgeon may advance only the flexible shaft up thecolon and then reattachment the SBR portion to the distal end once itemerges from the distal end of the bowel.) The surgeon then couples theanvil 202 to the advancing and retracting member 208 a by rotation ofthe corresponding drive shaft 136 a. Subsequent reverse biasing andtriggering of the same motor in the handle 100 causes the anvil 202 toretract toward the SBR portion 204. Once the electromagnetic sensors 240a, 240 b mounted on the undersurface of the anvil 202 and the outer edgeof the SBR housing come into adjacency sufficient to close the LCDindicator circuit 120, the LCD lightens on the handle. This signals thesurgeon operator to trigger the second shafts 136 b and 206 b intorotation, and advances the staple driver, blade and staplessimultaneously. The blade cuts through the stapled-closed ends of thecolon, leaving the tissue which has been severed in the interiorreservoir. Simultaneous with the cutting, the freshly opened ends arejoined together by the series of staples which are advanced throughholes in the perimeter edge of the SBR (being pressed against and closedby the opposing face of the anvil). The attachment and the flexibleshaft are then withdrawn from the patient.

While there has been described and illustrated new and novel carriageassemblies for use with surgical instruments such as electromechanicaldriver assembly coupleable to surgical attachments such as linearclamping and stapling attachments and an anastomosing and staplingattachment, it will be apparent to those skilled in the art thatvariations and modifications are possible without deviating from thebroad spirit and principle of the present invention which shall belimited solely by the scope of the claims appended hereto.

What is claimed is:
 1. An electromechanical assembly, comprising a) atleast one selectively engageable steering motor for engaging a steeringwire, b) at least one spring means for biasing said steering wire towarda taut state, and c) at least one selectively engageable carriage motorfor overcoming the bias created by said spring means.
 2. Theelectromechanical assembly of claim 1, wherein said steering motormechanically communicates with a pulley around which said steering wireis coiled to selectively rotate said pulley to selectively advance orretract said steering wire.
 3. The electromechanical assembly of claim1, wherein said at least one steering motor includes a plurality ofsteering motors, each of which is for engaging a separate steering wire,which engagement translates to enable the selective direction of aflexible shaft within a spatial plane.
 4. The electromechanical assemblyof claim 3, wherein said at least one steering motor includes twosteering motors, a) the first of which is for engaging a first steeringwire, which engagement translates to enable the selective direction ofthe flexible shaft within a first spatial plane, and b) the second ofwhich is for engaging a second steering wire, which engagementtranslates to enable the selective direction of the flexible shaftwithin a second spatial plane which is perpendicular to said firstspatial plane.
 5. The electromechanical assembly of claim 4, wherein a)said first steering motor mechanically communicates with a first pulleyaround which said first steering wire is coiled to selectively rotatesaid pulley to selectively advance or retract said first steering wireand b) said second steering motor mechanically communicates with asecond pulley around which said second steering wire is coiled toselectively rotate said pulley to selectively advance or retract saidsecond steering wire.
 6. The electromechanical assembly of claim 5,further comprising at least one selectively engageable drive motor forengaging an attached drive shaft.
 7. The electromechanical assembly ofclaim 5, wherein a) said electromechanical assembly further comprises anassembly housing having an interior wall, b) said first steering motorand said second steering motor travel on a steering motor carriagewithin said assembly housing, c) said first pulley and said secondpulley travel on a pulley carriage within said assembly housing, d) saidspring means biases said pulley carriage away from said interior wall,and e) said carriage motor mechanically communicates with said pulleycarriage to selectively allow said pulley carriage to succumb to thebias of said spring means or push said pulley carriage toward saidinterior wall with a force great enough to overcome the bias of saidspring means.
 8. The electromechanical assembly of claim 7, furthercomprising at least one selectively engageable drive motor whichselectably rotates an attached drive shaft.
 9. The electromechanicalassembly of claim 1, wherein a) said electromechanical assembly furthercomprises an assembly housing having an interior wall, b) said steeringmotor travels on a steering motor carriage within said assembly housing,and c) said spring means biases said steering motor carriage away fromsaid interior wall.
 10. The electromechanical assembly of claim 9,wherein said carriage motor mechanically communicates with said steeringmotor carriage to selectively allow said steering motor carriage tosuccumb to the bias of said spring means or push said steering motorcarriage toward said interior wall with a force great enough to overcomethe bias of said spring means.
 11. The electromechanical assembly ofclaim 1, wherein a) said electromechanical assembly further comprises anassembly housing having an interior wall, b) said steering wire iscoiled around a pulley which travels on a pulley carriage within saidassembly housing, and c) said spring means biases said pulley carriageaway from said interior wall.
 12. The electromechanical assembly ofclaim 11, wherein said carriage motor mechanically communicates withsaid pulley carriage to selectively allow said pulley carriage tosuccumb to the bias of said spring means or push said pulley carriagetoward said interior wall with a force great enough to overcome the biasof said spring means.
 13. The electromechanical assembly of claim 12,further comprising at least one selectively engageable drive motor forengaging an attached drive shaft.
 14. The electromechanical assembly ofclaim 11, wherein a) said steering motor travels on a steering motorcarriage within said assembly housing, b) said steering motormechanically communicates with a pulley around which said steering wireis coiled, c) said pulley travels on a pulley carriage within saidassembly housing, and d) said spring means biases said pulley carriageaway from said interior wall.
 15. The electromechanical assembly ofclaim 14, wherein at least one of said steering motor carriage and saidpulley carriage travel on a carriage rail within said assembly housing.16. The electromechanical assembly of claim 14, wherein said carriagemotor mechanically communicates with said steering motor carriage toselectively allow said steering motor carriage to succumb to the bias ofsaid spring means or push said steering motor carriage toward saidinterior wall with a force great enough to overcome the bias of saidspring means.
 17. The electromechanical assembly of claim 14, whereinsaid carriage motor mechanically communicates with said pulley carriageto selectively allow said pulley carriage to succumb to the bias of saidspring means or push said pulley carriage toward said interior wall witha force great enough to overcome the bias of said spring means.
 18. Theelectromechanical assembly of claim 17, further comprising at least oneselectively engageable drive motor for engaging an attached drive shaft.19. The electromechanical assembly of claim 1, further comprising atleast one selectively engageable drive motor for engaging an attacheddrive shaft.